(a) Field of the Invention
The present invention relates to a power delivery system of a hybrid vehicle. More particularly, the present invention relates to a power delivery system of a hybrid vehicle for delivering power from an engine to a differential gear by using three shafts and two planetary gear sets so as to improve power delivery efficiency, to minimize volume of a system, and to be easily installed in a vehicle, compared with a conventional power delivery system using a chain.
(b) Description of the Related Art
In a conventional hybrid vehicle, an engine, a driving motor, and a generator are provided. The engine is a constituent element which generates power for driving a vehicle by using fuel, and delivers the generated power. The driving motor is a constituent element for generating power that is required when starting to drive (because efficiency of the driving motor is good at lower RPM). The generator is a constituent element for generating electric power and engine ignition. Therefore, the driving motor is used when starting to drive, and then outputs of the engine and the driving motor are used together. That is, the output of the engine and the output of the generator are integrally used.
According to such a conventional system, the outputs of the engine and the driving motor are delivered to a fourth shaft connected with a differential gear through two shafts (a second shaft and a third shaft) which are disposed between first and fourth shafts, and are offset from the first and fourth shafts. Therefore, a rotational power of the first shaft is delivered to the fourth shaft through the second shaft and the third shaft in order.
In addition, according to the conventional power delivery system of a hybrid vehicle, the first shaft and the second shaft are connected through a chain, and the rotational power of the first shaft is delivered to the second shaft 400 through the chain.
Therefore, since four shafts are required to deliver the power of the engine and the driving motor to the differential gear, and two shafts are connected through the chain, a large space for the power delivery system is problematically required. In addition, since only one planetary gear set is used for changing speed, the number of realizable speeds is limited.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.